pySim.esim.saip: Don't try to generate file contents for MF/DF/ADF

only EFs have data content

Change-Id: I02a54a3b2f73a0e9118db87f8b514d1dbf53971f

pySim/esim/saip/__init__.py

@@ -441,6 +441,8 @@ class File:
         into the asn.1 encoder.  If optimize is True, it will try to encode only the differences from the
         fillFileContent of the profile template.  Otherwise, the entire file contents will be encoded
         as-is."""
+        if not self.file_type in ['TR', 'LF', 'CY', 'BT']:
+            return []
         if not optimize:
             # simplistic approach: encode the full file, ignoring the template/default
             return [('fillFileContent', self.body)]